Reactor column hydraulics

Hydraulic analysis Using Figure 3.27, the appropriate gas superficial velocity and the column diameter for the heterogeneous flow regime can be selected. An appropriate choice for the reactor diameter and the superficial gas velocity is 0.5 m and 0.1 m/s, respectively. The height to diameter ratio in columns is greater than unity and a value of 5 is reasonable. Therefore, the value of 2.5 m has been selected for the column height. As a result, the reactor volume is equal to 0.49 m3. This volume is occupied by the reaction mixture, which is the gas, the liquid, and the solid phase. 

A schematic of the experimental system is shown in Fig. 1. One liter of culture liquid was added to a 2.8-L cylindrical glass column reactor, and 300 mL of cylindrical carrier was packed with rock wool. All of the tubing connections, stoppers, and seals in the column were made of butyl rubber. To prevent photodecomposition of vitamin B12, the outside of the whole device was covered with a vinyl sheet to shut out light. The digestion was carried out at 55°C and 20 d of hydraulic retention time (HRT). 

Among others, the FBNR concept was considered at the IAEA consultancy meeting on Small Reactors without On-site Refuelling in March 2004, attended by experts from 6 IAEA Member States and the comment on FBNR was as follows In particular, the consultancy noted that the innovative approach proposed in the Fixed Bed Nuclear Reactor (FNBR) concept (Federal University of Rio Grande Do Sul, Brazil) relating to hydraulically supported column of spherical fuel elements offers a good potential to serve as a method of passive control of core reactivity. This concept needs to be further developed and polished for its possible implementation in small reactors. ... 

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